In your second example, you are executing the command by typing it into the console. If that is the behavior you want to emulate, you can use the stuff command to have screen paste your text into the console to execute it.

This won't display anything to your open terminal, but when you reconnect to the screen, you should see the output of your command (assuming the screen was at a console window at the time you sent the command, which is the risk with this approach).

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